Friday, 8 July 2011

Solar Energy

We are seriously considering installing solar PV panels to help combat the rising electricity costs.  Being in a remote location we do not have the luxury of mains gas and cannot therefore take advantage of dual fuel discounts offered by the Utility companies.  (This is inherently unfair I believe as we cannot possibly have dual fuel).  We use a fair amount of electricity and our alternative to gas is oil.  We do luckily have a wood burning stove to heat the sitting room in the winter.

Photovoltaic (PV) solar panels convert the light into electricity, which you can use to power your home during the day (so it is then a good idea to run all your expensive electrical gadgets during this time). There is a tariff (known as the 'Feed-in Tariff' - FIT) available at the moment which makes it very attractive to install.  You receive a guaranteed fixed price for each unit of electricity generated (even if you use it yourself), plus a further payment for each unit of energy not required.  As you can't store the excess energy you can export (sell) it back to the National Grid.  At night and if you need more power than the panels generate, the excess comes off the grid, exactly as it did before the panels were fitted.  These FIT payments are in addition to the savings on electricity bills made by using electricity generated at home.

The Energy Saving Trust (EST) assess that a typical family can make some money.  They note that profitability will be affected by whether you're at home during the day, the system size and the location.

We believe that our savings will probably be higher than a typical family as there are five of us who are at home in the day.  We are looking to install just less than 4kWp too on a roof which faces SSW.  The other factor to bear in mind of course is that the electricity prices are only going to go one way and that is up.

Feed-in Tariffs (FITs).  An illustration of the finances.
A typical domestic solar electricity system, with an installation size of 2.7 kWp could earn around:-
  • £990 per year from the Generation Tariff.  (FIT)
  • £40 per year from the Export Tariff.  (FIT)
  • £140 per year reduction in current electricity bills.

Or another way of looking at it - figures are for Solar Photovoltaic 0 to 4 kW (Retro-fit):-
  • For every kWh you Generate you receive 43.3 pence.  (FIT)
  • For every kWh you Export (i.e. sell) a further 3.1 pence per kWh will be made for each unit not used and exported to the grid.  (FIT)
  • For every kWh you generate and use in the home will contribute to the reduction of your energy bills.
Obviously do your own sums.
Notes: The Generation Tariff is lower if your installation is greater than 4kWp.
The Export Tariff does not have to be paid from the energy company who supplies your electricity, you can choose a different energy company.  Some companies do not measure the actual amount fed back into the grid but assume a 50% export.
The FIT payments will also rise with inflation and are tax free.
The Government guarantees that the electricity companies must pay the Feed-in Tariff from solar PV for 25 years.
To be eligible for FITs you must have your system installed by a Microgeneration Certification Scheme member as electricity companies will only pay for the Feed-in Tariff if you use an MCS certificated installer and product.
EST predicts Feed-in Tariffs are "likely to be significantly reduced for systems installed after 1 April 2012". So if the sums do add up for you, you may want to act quickly.

Energy companies will install the PV panels for free, but for this they will receive the Feed-in Tariff themselves.  Using the above figures this will be approx 1,030 a year.  If you can afford the initial outlay of typically around £12,000 it will be more economical for you to keep the feed-in payments, which could net you £25,750 over 25 years. 

We can split the purchase costs here between the families; J and myself to pay half and Him and Her Next Door to pay the other half.  By reducing our own personal outlay for the solar panels this proposition seems even more attractive to me.

The left hand side of the garage roof may house the PV panels.
We have also looked at wind technology in the past but we do not have enough wind here to make it a viable alternative.  Experts say that you need an average wind speed of 8-14 miles per hour for your system to operate effectively.  We used an anemometer which had a data logging device that output to a PC (you can buy devices that have solar and wind data combined now).  We placed it on the top of the garage for 6 months, our most exposed outbuilding, but the results were disappointing.  You might find EST's field trial report on domestic wind turbines an interesting read if you want to evaluate the possibilities for yourself - click the 'Download  PDF' link.  We do have room for just under 4kWp of solar PV panels on our garage roof though which faces an advantageous SSW, so along with the fact that most of us either work from home or are retired, the figures really do seem to start to stack up.


Preseli Mags said...

I think PVs are a brilliant idea. We're thinking of the 'free' option for here - I need to measure the height of the loft. I'm also beginning to think - judging by how annoyingly windy it's been - that a windmill might be viable too. (Off now to click all those links!)

Rob-bear said...

Wonderful that you've done all this research, in terms of what's possible. Sadly, the process doesn't work in urban areas like ours, where we live in the shade of neighbours' houses and the urban forest. But I should think it would be excellent in rural areas.

the veg artist said...

I've been thinking of this. We have a large, south facing roof, and I'm home all day, plus hubby is here working from home some of the time. We do have mains gas, but even that is getting ridiculously expensive. It's a pity you can't sneak a feed from a water turbine!

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